Exposure control device for camera

Claim 1

An exposure control device for a photographic camera having a shutter comprising: (a) means for producing a digital signal in accordance with a code signal representative of a film sensitivity on a film cartridge; (b) means for converting the digital signal from said digital signal producing means to an analog signal corresponding to the digital signal; (c) means for producing a voltage proportional to absolute temperature; (d) first amplifying means having a first input terminal to receive the analog signal from said converting means, a second input terminal to receive the voltage from said voltage producing means and an output terminal; (e) feedback impedance means connected between the first input terminal and the output terminal of said first amplifying means, whereby said first amplifying means producing a voltage corresponding to the analog signal; (f) light sensitive means disposed to receive the light from an object to be photographed; (g) second amplifying means arranged to receive the voltage from said first amplifying means and for amplifying the output from said light sensitive means; (h) impedance means connected to a feedback path of said second amplifying means for logarithmically compressing the output from said light sensitive means; (i) variable impedance means connected to an output terminal of said second amplifying means and for expanding the output from said second amplifying means into the inverse-logarithmic output; (j) integrating capacitor means for integrating an output from said variable impedance means in accordance with the opening operation of said shutter; and (k) shutter triggering means for closing said shutter when the voltage accross said integrating capacitor means reaches a predetermined value.